A method for improving reduction deposition reaction efficiency for polysilicon production

Abstract

The invention provides a method for increasing the efficiency of a reductive deposition reaction for polycrystalline silicon production, wherein a dichlorosilane liquid and a trichlorosilane liquid are vaporized and superheated via an independent vaporizer and an independent superheater respectively; the superheated trichlorosilane gas, the superheated dichlorosilane gas and high-purity hydrogen stepwise enter in a static mixer with proper flow rates via respective flow rate control units to be mixed; the mixed gas enters in a mixed gas temperature control unit, and the temperature of the mixed gas is stepwise controlled; and the mixed gas is conveyed to a reductive deposition reactor, and reacted on the surface of a silicon bar in the deposition reactor to generate polycrystalline silicon. With the adoption of the method, the efficiency of the reductive deposition reaction can be increased; the generation of amorphous silicon during the deposition reaction process is effectively controlled, and the blockage of the amorphous silicon for the pipelines and the equipment of downstream devices is avoided; and simultaneously, airtight circulation for dichlorosilane during polycrystalline silicon production is realized, and the arrangement of an anti-disproportionation device for dichlorosilane and silicon tetrachloride is avoided.

Description

technical field [0001] The present invention relates to reduction deposition reaction in polysilicon production process. Background technique [0002] In the polysilicon production process, the reduction deposition reaction is the most important chemical reaction unit, which is directly related to the quality, output and production cost of the finished polysilicon. [0003] Reduction deposition reaction efficiency includes two aspects: the rate of deposition reaction and the production of amorphous silicon. The higher the deposition reaction rate, the smaller the amount of amorphous silicon produced, indicating the higher the efficiency of the deposition reaction; otherwise, the lower the efficiency. [0004] At present, the known polysilicon production method is to supply the purified trichlorosilane and purified hydrogen into the polysilicon reduction deposition reactor in a certain molar ratio, and carry out the chemical deposition reaction at a temperature of 1080-1100 ...

AI Technical Summary

Problems solved by technology

When the reduction deposition reaction reaches a certain stage, the diameter of the silicon rod increases, and the temperature in the deposition reactor rises. At this time, dichlorodihydrogen silicon is easily decomposed in the gap between the silicon rods in the reactor, forming an amorphous silicon, resulting in a great waste of materials, and the efficiency of the corresponding reaction will also be reduced; at the same time, the amorphous silicon attached to the reduction deposition reactor is also not conducive to the normal production

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